pandas snippet 2

pandas_snippets_2.py

# If you want to filter rows by a certain number of columns with null values, you may use this:
df.iloc[df[(df.isnull().sum(axis=1) >= qty_of_nuls)].index]

# update each value in column while iterating over the dataframe row by row
for index_label, row_series in df.iterrows():
   # For each row update the 'Bonus' value to it's double
   df.at[index_label, 'Bonus'] = row_series['Bonus'] * 2
 
# select column by multiple range
df_10_2_rank.iloc[:, np.r_[0,16:31]]

# select row by list length
df_single = df_multiple[df_multiple['Sub Indicator'].map(len)==1]

# group dataframe rows into list in pandas groupby
# single row
df.groupby('a')['b'].apply(list)
# multiple rows, need to select out the rows want to group
df.groupby('a').agg(list)
df.groupby('a').agg(pd.Series.tolist)